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Old 02-25-2012, 01:32 AM
Pandu Poluan
 
Default Safe way to test a new kernel?

On Feb 25, 2012 9:14 AM, "Grant" <emailgrant@gmail.com> wrote:

>

> >> I need to test a kernel config change on a remote system. *Is there a

> >> safe way to do this? *The fallback thing in grub has never worked for

> >> me. *When does that ever work?

> >

> >

> > You can press ESC in the Grub screen and it will take you to text-only mode.

> > *There, you select an entry, press "e" and edit it. *Press ENTER when you're

> > finished, and then press "b" to boot your modified entry.

> >

> > That way, you can boot whatever kernel you want if the current one doesn't

> > work.

>

> I can't do that remotely though. *I'm probably asking for something

> that doesn't exist.

>

> - Grant

>


Situations like these that made me decide with great conviction to always deploy my servers virtualized, even if the box in question will only host a single VM.


Now, if I lost my intelligence for a couple of seconds and somehow ended up with a VM that's no longer accessible remotely, I just connect to the virtual console.


The flip side? Now I'm getting too daring/careless, and the uptime now drops below my (self-imposed) target of 99.99% :-P


Rgds,
 
Old 02-25-2012, 07:57 AM
Robert David
 
Default Safe way to test a new kernel?

V Fri, 24 Feb 2012 18:08:43 -0800
Grant <emailgrant@gmail.com> napsáno:

> >> I need to test a kernel config change on a remote system. *Is
> >> there a safe way to do this? *The fallback thing in grub has never
> >> worked for me. *When does that ever work?
> >
> >
> > You can press ESC in the Grub screen and it will take you to
> > text-only mode. There, you select an entry, press "e" and edit it.
> > *Press ENTER when you're finished, and then press "b" to boot your
> > modified entry.
> >
> > That way, you can boot whatever kernel you want if the current one
> > doesn't work.
>
> I can't do that remotely though. I'm probably asking for something
> that doesn't exist.
>
> - Grant
>

Don't do that if you don't have some tool like KVM, or other remote
management of the server. Or if it is available in the data center,
just call them and order this service for the time you need to do
updates.

This is why I don't use gentoo on servers any more, just because
I rather stay safe than sorry.

But if you really need to do that (and you don't have any chance to
get KVM attached), just create an virtual machine with backup of your
server and test that kernel there, and check that you have all the
modules you need on the server. But this is the last thing I would do.


Good luck,
Robert.
 
Old 02-25-2012, 11:18 AM
Mick
 
Default Safe way to test a new kernel?

On Saturday 25 Feb 2012 02:32:49 Pandu Poluan wrote:
> On Feb 25, 2012 9:14 AM, "Grant" <emailgrant@gmail.com> wrote:
> > >> I need to test a kernel config change on a remote system. Is there a
> > >> safe way to do this? The fallback thing in grub has never worked for
> > >> me. When does that ever work?
> > >
> > > You can press ESC in the Grub screen and it will take you to text-only
>
> mode.
>
> > > There, you select an entry, press "e" and edit it. Press ENTER when
>
> you're
>
> > > finished, and then press "b" to boot your modified entry.
> > >
> > > That way, you can boot whatever kernel you want if the current one
>
> doesn't
>
> > > work.
> >
> > I can't do that remotely though. I'm probably asking for something
> > that doesn't exist.
> >
> > - Grant
>
> Situations like these that made me decide with great conviction to always
> deploy my servers virtualized, even if the box in question will only host a
> single VM.
>
> Now, if I lost my intelligence for a couple of seconds and somehow ended up
> with a VM that's no longer accessible remotely, I just connect to the
> virtual console.
>
> The flip side? Now I'm getting too daring/careless, and the uptime now
> drops below my (self-imposed) target of 99.99% :-P

What do you do when you need to upgrade the host, rather than the guest?

--
Regards,
Mick
 
Old 02-25-2012, 11:33 AM
Nilesh Govindrajan
 
Default Safe way to test a new kernel?

On Sat 25 Feb 2012 05:48:49 PM IST, Mick wrote:
> On Saturday 25 Feb 2012 02:32:49 Pandu Poluan wrote:
>> On Feb 25, 2012 9:14 AM, "Grant" <emailgrant@gmail.com> wrote:
>>>>> I need to test a kernel config change on a remote system. Is there a
>>>>> safe way to do this? The fallback thing in grub has never worked for
>>>>> me. When does that ever work?
>>>>
>>>> You can press ESC in the Grub screen and it will take you to text-only
>>
>> mode.
>>
>>>> There, you select an entry, press "e" and edit it. Press ENTER when
>>
>> you're
>>
>>>> finished, and then press "b" to boot your modified entry.
>>>>
>>>> That way, you can boot whatever kernel you want if the current one
>>
>> doesn't
>>
>>>> work.
>>>
>>> I can't do that remotely though. I'm probably asking for something
>>> that doesn't exist.
>>>
>>> - Grant
>>
>> Situations like these that made me decide with great conviction to always
>> deploy my servers virtualized, even if the box in question will only host a
>> single VM.
>>
>> Now, if I lost my intelligence for a couple of seconds and somehow ended up
>> with a VM that's no longer accessible remotely, I just connect to the
>> virtual console.
>>
>> The flip side? Now I'm getting too daring/careless, and the uptime now
>> drops below my (self-imposed) target of 99.99% :-P
>
> What do you do when you need to upgrade the host, rather than the guest?
>

I think setting up a VM on the server using the new kernel should help
test a new kernel?

--
Nilesh Govindarajan
http://nileshgr.com
 
Old 02-25-2012, 11:46 AM
Francisco Ares
 
Default Safe way to test a new kernel?

On Sat, Feb 25, 2012 at 12:26 AM, Dale <rdalek1967@gmail.com> wrote:

Grant wrote:

>>> I need to test a kernel config change on a remote system. *Is there a

>>> safe way to do this? *The fallback thing in grub has never worked for

>>> me. *When does that ever work?

>>

>>

>> You can press ESC in the Grub screen and it will take you to text-only mode.

>> *There, you select an entry, press "e" and edit it. *Press ENTER when you're

>> finished, and then press "b" to boot your modified entry.

>>

>> That way, you can boot whatever kernel you want if the current one doesn't

>> work.

>

> I can't do that remotely though. *I'm probably asking for something

> that doesn't exist.

>

> - Grant

>

>





There is a couple people on here that handle remote machines. *I'd be

shocked if there isn't a way to do this. *Just give them a bit to see

the thread. *I vaguely recall someone mentioning this but since my

remote machine is about 20 feet away, I didn't make notes.



Dale



:-) *:-)



--

I am only responsible for what I said ... Not for what you understood or

how you interpreted my words!



Miss the compile output? *Hint:

EMERGE_DEFAULT_OPTS="--quiet-build=n"




That's right, there are many embedded machines out there with upgrades once in a while.*
Perhaps you would get better results asking at gentoo-embedded list.
Francisco
 
Old 02-25-2012, 12:47 PM
Nikos Chantziaras
 
Default Safe way to test a new kernel?

(Hmm, GMane acting up again. Sorry if this shows up twice; I've sent
this yesterday.)


On 25/02/12 04:00, Grant wrote:

I need to test a kernel config change on a remote system. Is there a
safe way to do this? The fallback thing in grub has never worked for
me. When does that ever work?


Oh crap, you said "remote system". Somehow I missed that. Ignore my
previous post since obviously accessing Grub on a remote machine would
require a hardware VNC module (if you had that, then you wouldn't have
posted about the issue in the first place, I assume.)


The way I dealt with it, is to use the "boot once" functionality of Grub:

http://weichong78.blogspot.com/2007/04/grub-test-kernel-once.html

I didn't bother with the panic handler, since I had remote hard-reset
functionality (I recommend it; it can save your day.)
 
Old 02-25-2012, 12:52 PM
Pandu Poluan
 
Default Safe way to test a new kernel?

On Feb 25, 2012 7:22 PM, "Mick" <michaelkintzios@gmail.com> wrote:

>

> On Saturday 25 Feb 2012 02:32:49 Pandu Poluan wrote:

> > On Feb 25, 2012 9:14 AM, "Grant" <emailgrant@gmail.com> wrote:

> > > >> I need to test a kernel config change on a remote system. *Is there a

> > > >> safe way to do this? *The fallback thing in grub has never worked for

> > > >> me. *When does that ever work?

> > > >

> > > > You can press ESC in the Grub screen and it will take you to text-only

> >

> > mode.

> >

> > > > *There, you select an entry, press "e" and edit it. *Press ENTER when

> >

> > you're

> >

> > > > finished, and then press "b" to boot your modified entry.

> > > >

> > > > That way, you can boot whatever kernel you want if the current one

> >

> > doesn't

> >

> > > > work.

> > >

> > > I can't do that remotely though. *I'm probably asking for something

> > > that doesn't exist.

> > >

> > > - Grant

> >

> > Situations like these that made me decide with great conviction to always

> > deploy my servers virtualized, even if the box in question will only host a

> > single VM.

> >

> > Now, if I lost my intelligence for a couple of seconds and somehow ended up

> > with a VM that's no longer accessible remotely, I just connect to the

> > virtual console.

> >

> > The flip side? Now I'm getting too daring/careless, and the uptime now

> > drops below my (self-imposed) target of 99.99% :-P

>

> What do you do when you need to upgrade the host, rather than the guest?

>


Since I'm using XenServer, upgrading the host is a well-defined procedure: Either I push the update using XenCenter, or I visit the servers. Usually, I just push minor updates using XenCenter.


Rgds,
 
Old 02-25-2012, 01:04 PM
Alan Mackenzie
 
Default Safe way to test a new kernel?

Hello, Nikos.

On Sat, Feb 25, 2012 at 04:10:10AM +0200, Nikos Chantziaras wrote:
> On 25/02/12 04:00, Grant wrote:
> > I need to test a kernel config change on a remote system. Is there a
> > safe way to do this? The fallback thing in grub has never worked for
> > me. When does that ever work?

> Oh crap, you said "remote system". Somehow I missed that. Ignore my
> previous post since obviously accessing Grub on a remote machine would
> require a hardware VNC module (if you had that, then you wouldn't have
> posted about the issue in the first place, I assume.)

> The way I dealt with it, is to use the "boot once" functionality of Grub:

> http://weichong78.blogspot.com/2007/04/grub-test-kernel-once.html

> I didn't bother with the panic handler, since I had remote hard-reset
> functionality (I recommend it; it can save your day.)

What is this "remote hard-reset functionality", if you don't mind me
asking? Do you mean somebody on the far end of a telephone line?

--
Alan Mackenzie (Nuremberg, Germany).
 
Old 02-25-2012, 02:23 PM
Nikos Chantziaras
 
Default Safe way to test a new kernel?

On 25/02/12 16:04, Alan Mackenzie wrote:

Hello, Nikos.

On Sat, Feb 25, 2012 at 04:10:10AM +0200, Nikos Chantziaras wrote:

On 25/02/12 04:00, Grant wrote:

I need to test a kernel config change on a remote system. Is there a
safe way to do this? The fallback thing in grub has never worked for
me. When does that ever work?



Oh crap, you said "remote system". Somehow I missed that. Ignore my
previous post since obviously accessing Grub on a remote machine would
require a hardware VNC module (if you had that, then you wouldn't have
posted about the issue in the first place, I assume.)



The way I dealt with it, is to use the "boot once" functionality of Grub:



http://weichong78.blogspot.com/2007/04/grub-test-kernel-once.html



I didn't bother with the panic handler, since I had remote hard-reset
functionality (I recommend it; it can save your day.)


What is this "remote hard-reset functionality", if you don't mind me
asking? Do you mean somebody on the far end of a telephone line?


No, it was a web interface button. It was instant. I assume it either
cut the power to the slice or a controller was hooked up to the reset
connector.
 
Old 02-25-2012, 05:30 PM
Grant
 
Default Safe way to test a new kernel?

>> I need to test a kernel config change on a remote system. *Is there a
>> safe way to do this? *The fallback thing in grub has never worked for
>> me. *When does that ever work?
>
>
> Oh crap, you said "remote system". *Somehow I missed that. *Ignore my
> previous post since obviously accessing Grub on a remote machine would
> require a hardware VNC module (if you had that, then you wouldn't have
> posted about the issue in the first place, I assume.)
>
> The way I dealt with it, is to use the "boot once" functionality of Grub:
>
> http://weichong78.blogspot.com/2007/04/grub-test-kernel-once.html

Perfect! That's exactly what I need. Here is an alternate method too:

http://fabbritech.blogspot.com/2009/07/make-grub-boot-something-once.html

I will test this ASAP.

- Grant
 

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